-LRB- CNN -RRB- -- `` I AM '' is a new CNN.com feature built on the belief that the labels we use for one another do n't really reveal who we are .

We present a collection of people who may surprise you . They not only defy their labels , but they 've done it in very public and dramatic ways .

This week , I AM presents four African-Americans who challenge conventional notions of blackness . But then defining what it means to be black has long been a matter of debate within the African-American community . The R&B singer , Billy Paul , once had a song called , `` Am I Black Enough ? '' Well are they ? You be the judge . Barbara Hillary -- At the age of 75 , she became the first African American woman to reach the North Pole .

Maurice Ashley -- Is the first and only African American to attain the coveted title of International Grand Master of Chess . Bliss Broyard -- Author of `` One Drop : My Father 's Hidden Life -- A Story of Race & Family Secrets , '' learned her father was black just before his death . Marvin Perkins -- As an African American elder in the Mormon church , Perkins says he is one of the world 's best kept secrets in the world .

@highlight

`` I AM '' is built on the belief that the labels we use for others , do n't reveal who we are

@highlight

Meet four African Americans who challenge conventional notions of blackness

@highlight

CNN Presents : Black in America airs July 23 and 24 , at 9 p.m. ET